This build will use the Fighter, Sorcerer and Spellsword classes.
The duskblade might make this a little bit better, but you would have less long range spells. If you don't do that you should switch the first and second level classes. It would give you 8 more hp.

Now, some might think, "Why??"
My answer is, "A high-level Sorcerer with the ability to wear Full Plate scares me. Why doesn't it scare you?"
The Spellsword's ability to ignore spell failures is incredibly powerful. After all, it clears up the Sorcerer's main weakness, AC (that and health, but the spellsword's d8 hit die helps there).
Also, the Spellsword has the best BAB progression in the game, which helps the character perform in melee.

The sorcerer levels can be replaced by Wizard or Hexblade levels. Wizard levels allow you to reach the requirement for Spellsword a level faster, but I chose Sorcerer since I hate having to prepare spells. Hexblade levels, on the other hand, take longer to reach the Spellsword requirement, but are generally better at melee, which helps complete the combat requirement of the Spellsword.
(In order to become a Spellsword, one needs to be able to cast 2nd-level arcane spells).

If the character wears Full Plate, it still has a 5% Arcane Spell Failure chance (unless the armor is made of Mithral). Wearing a Breastplate eliminates this at the cost of some AC. If the character is wearing a Breastplate or Mithral Full Plate, he/she may take a shield and still have no Arcane Spell Failure chance.

Make the combat required to be eligible for the Spellsword harder, therefore making it more difficult to complete this build. Players, in order to complete the fight, wear your team's fighter's armor and wield a high-damage weapon!

The Fighter level is there in order to make it possible for the character to gain proficiency with all simple and martial weapons as well as with all armor, since this is both helpful for the build and required to be eligible for the Spellsword Prestige Class.